The invention relates to a method of fabricating a part out of ceramic matrix composite (CMC) material, in which the matrix is formed by melt infiltration (MI), i.e. infiltrating a composition based on silicon in the molten state.
A field of application of the invention is making parts that are to be exposed to high temperatures in service, specifically in the fields of aviation and space, in particular parts for the hot portions of aviation turbine engines, it being understood that the invention can be applied to other fields, e.g. to the field of industrial gas turbines.
CMC materials present good thermostructural properties, i.e. good mechanical properties that make them suitable for constituting structural parts, together with the ability to conserve those properties at high temperatures. The use of CMC materials instead of metal materials for parts that are exposed to high temperatures in service has therefore been recommended, particularly since such materials present density that is considerably less than the density of the metal materials they replace.
A well known method for fabricating CMC parts consists in making a preform from fiber plies made of silicon carbide fibers, then in introducing a silicon carbide powder into the resulting preform, and then in infiltrating the resulting powder-filled preform with molten silicon so as to form a ceramic matrix. The MI method presents the advantage of being much faster and easier to perform than densification by chemical vapor infiltration (CVI). It is nevertheless desirable to further improve the mechanical performance of CMC parts as obtained in this way.
Also known is EP 1 391 442, which, in its paragraph [0011], teaches a technical solution that is closely associated with the situation in which the matrix is formed by sintering a powder.
There therefore exists a need to improve the mechanical properties of ceramic matrix composite material parts obtained by melt infiltration of a silicon-based composition.